1. Field of the Invention
The present invention relates to a power transmission device for transmitting torque of a driving unit such as an engine and an electric motor to a driven unit such as a pump and a compressor. More specifically, the device is useful for transmitting engine power to the compressor of a vehicle air conditioner.
2. Description of the Related Art
FIG. 2 shows a power transmission prototype device made by the inventors. This prototype was subjected to an endurance test under a high load condition, the result being the breaking of the rubber dampers 140, or torque transmission members. Then, research on the cause of the damper breakage was made to show that when the foregoing prototype is transmitting torque, the dampers undergo a deforming force. Then, due to the action of heat generation resulting from viscous resistance at the time of the damper deformation, the dampers rise in temperature and suffer oxidation and degradation at their outer peripheries which are exposed directly to the air, resulting in breakage.